Intervertebral prosthesis placement instrument

Abstract

The invention concerns an intervertebral prosthesis placement instrument which can be used to facilitate accurate positioning of a spinal disc prosthesis between adjacent spinal vertebrae. The instrument ( 10 ) has opposed jaws 12 formed with tips ( 24 ) that are shaped for insertion between the vertebrae. The jaws can be moved apart from one another to distract the vertebrae, allowing the prosthesis to enter between the vertebrae. The jaws also have opposed surfaces which are shaped to embrace the prosthesis between them and to guide the prosthesis into position.

What is claimed is: 
     
       1. A method for implanting an intervertebral prosthesis, the method comprising:
 inserting a prosthesis having two vertebral contacting surfaces and at least one fin projecting from at least one of the two vertebral contacting surfaces into a placement instrument comprising opposed jaws, with the at least one fin slidably received in at least one slot in the opposed jaws and the opposed jaws being inclined toward tips of one another to define a gap in the placement instrument opposite the tips for insertion of the prosthesis; 
 inserting the tips of the opposed jaws between adjacent vertebrae; 
 moving the jaws apart from one another to cause distraction of the vertebrae; and 
 implanting the prosthesis by sliding the at least one fin of the prosthesis in the at least one slot of the jaws and guiding the at least one fin of the prosthesis into a vertebral slot cut into at least one of the vertebrae. 
 
     
     
       2. A method according to  claim 1 , wherein the step of moving the jaws apart from one another is performed by driving the prosthesis downward in the jaws to force the jaws and the vertebrae apart. 
     
     
       3. A method according to  claim 1 , wherein the at least one fin comprises a fin on each of the two vertebral contacting surfaces and wherein the at least one slot of the jaws comprises a slot on each of the opposing inner surfaces of the jaws. 
     
     
       4. A method according to  claim 1 , further comprising an initial step of cutting the vertebral slot into one of the vertebrae. 
     
     
       5. A method for implanting an intervertebral prosthesis, the method comprising:
 providing a placement instrument comprising opposed jaws and at least one slot in the opposed jaws configured to receive at least one fin of a prosthesis, the opposed jaws being inclined toward tips of one another to define a gap in the placement instrument opposite the tips; 
 inserting the tips of the opposed jaws between adjacent vertebrae; 
 moving the jaws apart from one another to cause distraction of the vertebrae; 
 inserting a prosthesis having two vertebral contacting surfaces and the at least one fin projecting from at least one of the two vertebral contacting surfaces into the gap in the placement instrument with the at least one fin of the prosthesis received in the at least one slot of the jaws; and 
 implanting the prosthesis by sliding the at least one fin of the prosthesis in the at least one slot of the jaws and guiding the at least one fin of the prosthesis into a vertebral slot cut into one of the vertebrae. 
 
     
     
       6. A method according to  claim 5 , wherein the step of moving the jaws apart from one another is performed by manipulation of a pair of handles of the placement instrument. 
     
     
       7. A method according to  claim 5 , wherein the at least one fin comprises a fin on each of the two vertebral contacting surfaces and wherein the at least one slot of the jaws comprises a slot on each of the opposing inner surfaces of the jaws. 
     
     
       8. A method according to  claim 5 , further comprising an initial step of cutting the vertebral slot into one of the vertebrae. 
     
     
       9. A method according to  claim 1 , wherein the at least one slot of the jaws comprises two substantially parallel side walls, wherein the at least one fin comprises two substantially parallel side walls and the spacing of the side walls of the slot of the jaws is configured to fit and guide the at least one fin. 
     
     
       10. A method according to  claim 5 , wherein the at least one slot of the jaws comprises two substantially parallel side walls, wherein the at least one fin comprises two substantially parallel side walls and the spacing of the side walls of the slot of the jaws is configured to fit and guide the at least one fin.